Address comments: simplify, dedupe and clean up

Author: sandersn

src/compiler/checker.ts

@@ -18110,18 +18110,17 @@ namespace ts {
 
                     forEach(overloads, o => {
                         const deviation = getEffectiveDeclarationFlags(o, flagsToCheck) ^ canonicalFlags;
-                        const name = getNameOfDeclaration(o);
                         if (deviation & ModifierFlags.Export) {
-                            error(name, Diagnostics.Overload_signatures_must_all_be_exported_or_non_exported);
+                            error(getNameOfDeclaration(o), Diagnostics.Overload_signatures_must_all_be_exported_or_non_exported);
                         }
                         else if (deviation & ModifierFlags.Ambient) {
-                            error(name, Diagnostics.Overload_signatures_must_all_be_ambient_or_non_ambient);
+                            error(getNameOfDeclaration(o), Diagnostics.Overload_signatures_must_all_be_ambient_or_non_ambient);
                         }
                         else if (deviation & (ModifierFlags.Private | ModifierFlags.Protected)) {
-                            error(name || o, Diagnostics.Overload_signatures_must_all_be_public_private_or_protected);
+                            error(getNameOfDeclaration(o) || o, Diagnostics.Overload_signatures_must_all_be_public_private_or_protected);
                         }
                         else if (deviation & ModifierFlags.Abstract) {
-                            error(name, Diagnostics.Overload_signatures_must_all_be_abstract_or_non_abstract);
+                            error(getNameOfDeclaration(o), Diagnostics.Overload_signatures_must_all_be_abstract_or_non_abstract);
                         }
                     });
                 }
@@ -20317,19 +20316,12 @@ namespace ts {
                     return;
                 }
 
-                let errorNode: Node;
-                if (propDeclaration && propDeclaration.kind === SyntaxKind.BinaryExpression) {
-                    const specialAssignmentKind = getSpecialPropertyAssignmentKind(propDeclaration as BinaryExpression);
-                    if (specialAssignmentKind === SpecialPropertyAssignmentKind.Property ||
-                        specialAssignmentKind === SpecialPropertyAssignmentKind.PrototypeProperty ||
-                        specialAssignmentKind === SpecialPropertyAssignmentKind.ThisProperty) {
-                        errorNode = propDeclaration;
-                    }
-                }
                 // perform property check if property or indexer is declared in 'type'
-                // this allows to rule out cases when both property and indexer are inherited from the base class
+                // this allows us to rule out cases when both property and indexer are inherited from the base class
+                let errorNode: Node;
                 if (propDeclaration &&
-                    (getNameOfDeclaration(propDeclaration).kind === SyntaxKind.ComputedPropertyName ||
+                    (propDeclaration.kind === SyntaxKind.BinaryExpression ||
+                     getNameOfDeclaration(propDeclaration).kind === SyntaxKind.ComputedPropertyName ||
                      prop.parent === containingType.symbol)) {
                     errorNode = propDeclaration;
                 }

src/compiler/utilities.ts

@@ -1784,21 +1784,21 @@ namespace ts {
             const kind = getSpecialPropertyAssignmentKind(declaration);
             const lhs = (declaration as BinaryExpression).left;
             switch (kind) {
-            case SpecialPropertyAssignmentKind.None:
-            case SpecialPropertyAssignmentKind.ModuleExports:
-                return undefined;
-            case SpecialPropertyAssignmentKind.ExportsProperty:
-                if (lhs.kind === SyntaxKind.Identifier) {
+                case SpecialPropertyAssignmentKind.None:
+                case SpecialPropertyAssignmentKind.ModuleExports:
+                    return undefined;
+                case SpecialPropertyAssignmentKind.ExportsProperty:
+                    if (lhs.kind === SyntaxKind.Identifier) {
+                        return (lhs as PropertyAccessExpression).name;
+                    }
+                    else {
+                        return ((lhs as PropertyAccessExpression).expression as PropertyAccessExpression).name;
+                    }
+                case SpecialPropertyAssignmentKind.ThisProperty:
+                case SpecialPropertyAssignmentKind.Property:
                     return (lhs as PropertyAccessExpression).name;
-                }
-                else {
+                case SpecialPropertyAssignmentKind.PrototypeProperty:
                     return ((lhs as PropertyAccessExpression).expression as PropertyAccessExpression).name;
-                }
-            case SpecialPropertyAssignmentKind.ThisProperty:
-            case SpecialPropertyAssignmentKind.Property:
-                return (lhs as PropertyAccessExpression).name;
-            case SpecialPropertyAssignmentKind.PrototypeProperty:
-                return ((lhs as PropertyAccessExpression).expression as PropertyAccessExpression).name;
             }
         }
         else {
@@ -2025,7 +2025,8 @@ namespace ts {
      *      Symbol.
      */
     export function hasDynamicName(declaration: Declaration): boolean {
-        return getNameOfDeclaration(declaration) && isDynamicName(getNameOfDeclaration(declaration));
+        const name = getNameOfDeclaration(declaration);
+        return name && isDynamicName(name);
     }
 
     export function isDynamicName(name: DeclarationName): boolean {